PyroSim UG

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PyroSim User Manual

2016


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PyroSim User Manual


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Table of Contents

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Table of ContentsPyroSim User Manual ............................................................................................................. ii

Table of Contents .................................................................................................................. iv

Figures ................................................................................................................................ viii

Disclaimer ............................................................................................................................ xii

Acknowledgements............................................................................................................. xiii

Chapter 1. Getting Started ......................................................................................................1

Introduction ................................................................................................................................. 1

Download and Install ................................................................................................................... 1

Some Modeling Suggestions ........................................................................................................ 2

Using a Different FDS Executable................................................................................................. 4

Additional FDS and Smokeview Documentation ......................................................................... 4

Contact Us .................................................................................................................................... 4

Chapter 2. PyroSim Basics ......................................................................................................5

PyroSim Interface ......................................................................................................................... 5

Navigation View ........................................................................................................................... 53D View ........................................................................................................................................ 6

2D View ...................................................................................................................................... 10

Record View ............................................................................................................................... 10

Snapshots of Display .................................................................................................................. 11

Preferences ................................................................................................................................ 11

Units ........................................................................................................................................... 14

Color Schemes ............................................................................................................................ 14

Chapter 3. Views .................................................................................................................. 16

Managing Views ......................................................................................................................... 16

Viewpoints ................................................................................................................................. 17

Section Boxes ............................................................................................................................. 18

Smokeview Interoperability ....................................................................................................... 19

Chapter 4. Working with Files ............................................................................................... 21

Creating a New PyroSim Model ................................................................................................. 21

Saving a PyroSim Model ............................................................................................................. 21

Open a Saved PyroSim Model .................................................................................................... 21

Preventing Changes to a Model ................................................................................................. 21

Importing FDS Models ............................................................................................................... 22

Exporting FDS Models ................................................................................................................ 22

Importing CAD files .................................................................................................................... 23

Chapter 5. Meshes ............................................................................................................... 31

Working with Meshes ................................................................................................................ 31

Uniform Meshes ........................................................................................................................ 31Nonuniform Meshes .................................................................................................................. 32

Using Multiple Meshes .............................................................................................................. 33

Additional Mesh Actions ............................................................................................................ 36

Chapter 6. Materials ............................................................................................................ 38

Solid Materials ........................................................................................................................... 38

Liquid Fuels ................................................................................................................................ 39

Chapter 7. Surfaces .............................................................................................................. 41


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Reserved Surfaces ...................................................................................................................... 41

Surface Types ............................................................................................................................. 42

Adding Textures to Surfaces ...................................................................................................... 48

Chapter 8. Geometry (Basic Concepts) .................................................................................. 49

Obstructions ............................................................................................................................... 49

Holes .......................................................................................................................................... 52

Vents .......................................................................................................................................... 53

Groups ........................................................................................................................................ 54

Floors.......................................................................................................................................... 56

Adding a Background Image to a Floor ...................................................................................... 58

Chapter 9. Drawing in PyroSim ............................................................................................. 60

Drawing/Editing Tool Overview ................................................................................................. 60

Snapping..................................................................................................................................... 62

Precise Keyboard Entry .............................................................................................................. 65

2D versus 3D Drawing ................................................................................................................ 66

Obstruction Drawing Tools ........................................................................................................ 69

Hole Drawing Tools .................................................................................................................... 74

Vent Tool .................................................................................................................................... 74Solution Mesh Tool .................................................................................................................... 75

Mesh Splitter Tool ...................................................................................................................... 76

Device Tool ................................................................................................................................. 77

Planar Slice Tool ......................................................................................................................... 78

HVAC Node Tool ......................................................................................................................... 79

HVAC Duct Tool .......................................................................................................................... 80

Other Drawing Tools .................................................................................................................. 80

Editing Objects ........................................................................................................................... 81

Transforming Objects ................................................................................................................. 82

Painting Obstructions and Vents ............................................................................................... 85

Measuring Length/Distance ....................................................................................................... 86Chapter 10. Creating Complex Geometry .............................................................................. 88

Curved Walls .............................................................................................................................. 88

Trusses ....................................................................................................................................... 91

Roofs .......................................................................................................................................... 92

Stairs .......................................................................................................................................... 93

Chapter 11. Working with Geometry Objects ........................................................................ 95

Selection ..................................................................................................................................... 95

Context Menus ........................................................................................................................... 95

Undo/Redo ................................................................................................................................. 95

Copy/Paste ................................................................................................................................. 95

Double-Click to Edit .................................................................................................................... 96

Translate and Copy Dialog ......................................................................................................... 96

Mirror and Copy Dialog .............................................................................................................. 96

Scale and Copy Dialog ................................................................................................................ 97

Rotate and Copy Dialog.............................................................................................................. 98

Object Visibility .......................................................................................................................... 99

Chapter 12. Species ............................................................................................................ 100

Primitive Species ...................................................................................................................... 100

Lumped Species ....................................................................................................................... 101


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Chapter 13. Reactions ........................................................................................................ 102

Mixture Fraction Combustion .................................................................................................. 102

Custom Smoke ......................................................................................................................... 104

Chapter 14. Particles .......................................................................................................... 106

Massless Tracers ...................................................................................................................... 106

Liquid Droplets ......................................................................................................................... 106

Solid Particles ........................................................................................................................... 108

Activation ................................................................................................................................. 108

Global Parameters ................................................................................................................... 108

Particle Clouds ......................................................................................................................... 109

Chapter 15. Devices ........................................................................................................... 111

Aspiration Detection System ................................................................................................... 111

Gas or Solid Phase Device ........................................................................................................ 112

Thermocouple .......................................................................................................................... 113

Flow Measurement .................................................................................................................. 113

Heat Release Rate Device ........................................................................................................ 114

Layer Zoning Device ................................................................................................................. 114

Path Obscuration (Beam Detector) Device .............................................................................. 115Heat Detector ........................................................................................................................... 115

Smoke Detector ....................................................................................................................... 116

Sprinkler ................................................................................................................................... 116

Nozzle ....................................................................................................................................... 118

Chapter 16. Control Logic ................................................................................................... 119

Creating Activation Controls .................................................................................................... 119

Time-based Input ..................................................................................................................... 121

Detector-based Input ............................................................................................................... 121

Chapter 17. HVAC Systems ................................................................................................. 123

HVAC Duct ................................................................................................................................ 123

HVAC Node ............................................................................................................................... 124HVAC Fan.................................................................................................................................. 125

HVAC Filter ............................................................................................................................... 125

HVAC Aircoil ............................................................................................................................. 126

HVAC Vents .............................................................................................................................. 127

Chapter 18. Output Controls............................................................................................... 128

Solid Profiles............................................................................................................................. 128

Slices ......................................................................................................................................... 128

Boundary Quantities ................................................................................................................ 129

Isosurfaces ............................................................................................................................... 130

Plot3D Data .............................................................................................................................. 131

Statistics ................................................................................................................................... 133

Chapter 19. Running the Simulation ................................................................................... 135

Simulation Parameters............................................................................................................. 135

OpenMP Environment ............................................................................................................. 141

Run FDS .................................................................................................................................... 142

Parallel Execution ..................................................................................................................... 145

Cluster Execution ..................................................................................................................... 146

Resuming a Simulation ............................................................................................................. 147

Chapter 20. Post-Processing ............................................................................................... 148


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Launching Smokeview .............................................................................................................. 148

Time History Results ................................................................................................................ 148

Archiving Results ...................................................................................................................... 149

Restoring Archived Results ...................................................................................................... 149

Chapter 21. Managing Data Libraries .................................................................................. 151

Create and Manage Your Own Libraries .................................................................................. 151

Use the Library Provided with PyroSim ................................................................................... 151

Import a Material or Reaction from the FDS 4 Database ........................................................ 152

Chapter 22. Advanced FDS Parameters ............................................................................... 153

Additional Records Section ...................................................................................................... 153

Advanced Parameters .............................................................................................................. 154

Chapter 23. Troubleshooting .............................................................................................. 155

Floating License Server Problems ............................................................................................ 155

Licensing/Registration Problems ............................................................................................. 155

Video Display Problems ........................................................................................................... 155

Memory for Large Models ....................................................................................................... 155

Parallel Simulation (MPI) Problems ......................................................................................... 156

Contacting Technical Support .................................................................................................. 157Appendix A. Opening FDS v4 and PyroSim v2006 Files ......................................................... 158

Global Simulation Parameters ................................................................................................. 159

Sprinklers and Pipes ................................................................................................................. 160

Reactions .................................................................................................................................. 160

Surfaces .................................................................................................................................... 160

Thermally Thin Surfaces ........................................................................................................... 161

Where is the Surface Database? .............................................................................................. 161

Appendix B. Opening FDS v5 and PyroSim v2012 Files ......................................................... 162

Global Simulation Parameters ................................................................................................. 163

Reactions .................................................................................................................................. 163

Surfaces .................................................................................................................................... 164Particles .................................................................................................................................... 164

References ......................................................................................................................... 166


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Figures

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FiguresFigure 2.1. Using the context menu in the Navigation View ........................................................................ 6

Figure 2.2. 3D navigation toolbar ................................................................................................................. 6

Figure 2.3. Exterior view of model (PyroSim model by John McKinney) ...................................................... 7

Figure 2.4. Interior view of model looking at roof and bleachers ................................................................ 8

Figure 2.5. Floors drop-down ........................................................................................................................ 9

Figure 2.6. Filter toolbar ............................................................................................................................... 9

Figure 2.7. Mesh filter toolbar ...................................................................................................................... 9

Figure 2.8. Filtering mesh elements ............................................................................................................ 10

Figure 2.9 PyroSim preferences .................................................................................................................. 11

Figure 2.10 Record View Preferences ......................................................................................................... 12

Figure 2.11. FDS Preferences ...................................................................................................................... 13

Figure 2.12 Smokeview Preferences ........................................................................................................... 13

Figure 2.13. Display Preferences ................................................................................................................. 14

Figure 3.1: Views ......................................................................................................................................... 16

Figure 3.2: Effect of a Section Box (a) section box disabled (b) section box enabled ................................ 18

Figure 3.3: Section box properties dialog ................................................................................................... 19

Figure 4-1: CAD import dialog ..................................................................................................................... 24

Figure 4.2. STL Import Options dialog ......................................................................................................... 27

Figure 5.1. Defining properties of the new mesh ....................................................................................... 32

Figure 5.2. Defining properties of the nonuniform mesh ........................................................................... 33

Figure 5.3. 3D display of first and second mesh ......................................................................................... 33

Figure 5.4. Correct and incorrect mesh alignment ..................................................................................... 36

Figure 7.1. The Edit Surfaces dialog ............................................................................................................ 41

Figure 7.2. Effect of normal axis on the direction of tangential velocity .................................................... 45

Figure 8.1. Conversion of a slab obstruction to FDS blocks ........................................................................ 50

Figure 8.2. Obstruction dialog ..................................................................................................................... 50

Figure 8.3. A slab obstruction with a hole cut from it ................................................................................ 52

Figure 8.4. Hole Properties dialog ............................................................................................................... 53

Figure 8.5. Vents on a mesh boundary and obstruction ............................................................................. 53

Figure 8.6. New Vent dialog ........................................................................................................................ 54

Figure 8.7. Create Group dialog .................................................................................................................. 55

Figure 8.8. Dragging objects to a new group in the Navigation View ......................................................... 55Figure 8.9. The Change Group dialog .......................................................................................................... 56

Figure 8.10. The Group drop-down ............................................................................................................ 56

Figure 8.11: Floor clipping (a) shows all floors (b) shows a single floor ..................................................... 56

Figure 8.12. Manage Floors dialog .............................................................................................................. 57

Figure 8.13. New Floor dialog ..................................................................................................................... 58

Figure 8.14. Display of background image .................................................................................................. 59


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Figure 9.1. Drawing/Editing toolbar ............................................................................................................ 60

Figure 9.2. Pinning a drawing/editing tool ................................................................................................. 61

Figure 9.3. The quick action menu for the wall tool ................................................................................... 62

Figure 9.4. Snap indicator ........................................................................................................................... 62

Figure 9.5. Sketch grid ................................................................................................................................. 63

Figure 9.6. Polar constraint at an angle of 45 degrees ............................................................................... 64

Figure 9.7. Locked constraint ...................................................................................................................... 65

Figure 9.8. Tool editor window ................................................................................................................... 66

Figure 9.9. Precise keyboard entry ............................................................................................................. 66

Figure 9.10. Slabs in different planes aligned in the 2D View .................................................................... 67

Figure 9.11. Vent and devices attached to a wall ....................................................................................... 68

Figure 9.12. Objects stacked in the 3D View .............................................................................................. 68

Figure 9.13. Improper vs proper hole drawing in the 3D view ................................................................... 69

Figure 9.14. Snapping to another plane in the 3D View ............................................................................. 69

Figure 9.15. Tool properties dialog for obstructions .................................................................................. 70

Figure 9.16. A polygonal slab obstruction .................................................................................................. 71

Figure 9.17. A wall obstruction ................................................................................................................... 72

Figure 9.18. Wall alignment options ........................................................................................................... 72

Figure 9.19. Blocks drawn with the block obstruction tool ........................................................................ 73

Figure 9.20. A room drawn with the room tool .......................................................................................... 74

Figure 9.21. A solution mesh drawn with the mesh tool ............................................................................ 75

Figure 9.22. Two types of drawn meshes ................................................................................................... 76

Figure 9.23. Meshes being split by the mesh splitter tool .......................................................................... 77

Figure 9.24. A gas-phase device being drawn in the 3D View .................................................................... 78

Figure 9.25. Drawing a slice with the planar slice tool ............................................................................... 79

Figure 9.26. Using the HVAC Node drawing tool ........................................................................................ 79

Figure 9.27. Drawing an HVAC Duct............................................................................................................ 80

Figure 9.28. Editing handles on an object ................................................................................................... 81

Figure 9.29. A highlighted face handle ....................................................................................................... 82

Figure 9.30. Moving an object using the Move Tool .................................................................................. 83

Figure 9.31. Rotating an object with the Rotate Tool ................................................................................. 84

Figure 9.32. Mirroring an object using the Mirror Tool .............................................................................. 85

Figure 9.33. An obstruction face highlighted by the paint tool .................................................................. 86

Figure 9.34. Information displayed by the measure tool ........................................................................... 87

Figure 10.1. Background image used for all curved wall examples ............................................................ 88

Figure 10.2. Background image settings for curved wall examples ............................................................ 89

Figure 10.3. A curved wall drawn with three different segment lengths ................................................... 89

Figure 10.4. A curved wall drawn using individual blocks .......................................................................... 90

Figure 10.5. A curved wall drawn using the rotate technique .................................................................... 91

Figure 10.6. Trusses created using PyroSim tools ....................................................................................... 92

Figure 10.7. A roof created with the slab obstruction tool ........................................................................ 93

Figure 10.8. A stairway created with the replicate tool ............................................................................. 94


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Figure 11.1. The translate dialog ................................................................................................................ 96

Figure 11.2. The mirror dialog .................................................................................................................... 97

Figure 11.3. The scale dialog being used to scale an object ....................................................................... 98

Figure 11.4. The rotate dialog being used to rotate an object ................................................................... 99

Figure 13.1. Reaction equation ................................................................................................................. 102

Figure 13.2. Fuel panel of the Edit Reactions dialog ................................................................................. 103

Figure 13.3. Fire Suppression panel of the Edit Reactions dialog ............................................................. 104

Figure 13.4. Byproducts panel of the Edit Reactions dialog ..................................................................... 104

Figure 14.1. Particle Cloud dialog ............................................................................................................. 109

Figure 15.1. Creating an aspirator sampler .............................................................................................. 112

Figure 15.2. Creating a new sprinkler ....................................................................................................... 117

Figure 16.1. The Activation Controls dialog .............................................................................................. 119

Figure 16.2. The object popup in the Activation Controls dialog ............................................................. 120

Figure 16.3. The Activation Controls dialog .............................................................................................. 121

Figure 18.1. An example of a slice plane shown in Smokeview. ............................................................... 129

Figure 18.2. An example of a boundary quantity shown in Smokeview................................................... 130

Figure 18.3. An example of an isosurface shown in Smokeview .............................................................. 131

Figure 18.4. A velocity Plot3D data shown in Smokeview ........................................................................ 132

Figure 18.5. An example of statistic output .............................................................................................. 133

Figure 19.1. Time tab of the simulation parameters dialog ..................................................................... 135

Figure 19.2. Output tab of the simulation parameters dialog .................................................................. 136

Figure 19.3. Environment tab of the simulation parameters dialog......................................................... 137

Figure 19.4. Init Region dialog .................................................................................................................. 138

Figure 19.5. Angled Geometry tab of the simulation parameters dialog ................................................. 139

Figure 19.6. Merging converted blocks .................................................................................................... 140

Figure 19.7. Effect of thickening on converted blocks .............................................................................. 140

Figure 19.8. Misc. tab on the simulation parameters dialog .................................................................... 141

Figure 19.9. The OpenMP Environment dialog. ........................................................................................ 141

Figure 19.10. The FDS Toolbar .................................................................................................................. 142

Figure 19.11. The FDS simulation dialog ................................................................................................... 143

Figure 19.12. Expand Boundary Holes dialog ........................................................................................... 144

Figure 19.13. Hole along a mesh boundary .............................................................................................. 144

Figure 19.14. Improperly cut hole along mesh boundary in FDS .............................................................. 145

Figure 19.15. Properly cut hole along mesh boundary in FDS .................................................................. 145

Figure 19.16. The Cluster FDS Parameters dialog ..................................................................................... 147

Figure 20.1. Time History Results ............................................................................................................. 148

Figure 20.2. Archive FDS Results dialog .................................................................................................... 149

Figure 20.3. Restore Archived Results dialog ............................................................................................ 150

Figure 21.1. Creating a library of materials............................................................................................... 151

Figure 22.1. Additional Records Section ................................................................................................... 153

Figure 22.2. Additional Fields .................................................................................................................... 154

Figure A.1. Example import warnings ....................................................................................................... 159


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Figure B.1. Example import warnings ....................................................................................................... 162


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Disclaimer

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DisclaimerThunderhead Engineering makes no warranty, expressed or implied, to users of PyroSim, and accepts no

responsibility for its use. Users of PyroSim assume sole responsibility under Federal law for determining

the appropriateness of its use in any particular application, for any conclusions drawn from the results of

its use, and for any actions taken or not taken as a result of analyses performed using these tools.

Users are warned that PyroSim is intended for use only by those competent in the

fields of fluid dynamics, thermodynamics, combustion, and heat transfer, and is

intended only to supplement the informed judgment of the qualified user. The software

package is a computer model that may or may not have predictive capability when

applied to a specific set of factual circumstances. Lack of accurate predictions by

the model could lead to erroneous conclusions with regard to fire safety. All results

should be evaluated by an informed user.

Throughout this document, the mention of computer hardware or commercial software does not

constitute endorsement by Thunderhead Engineering, nor does it indicate that the products are

necessarily those best suited for the intended purpose.


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Acknowledgements

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AcknowledgementsWe thank Kevin McGrattan, Simo Hostikka, Randall McDermott, Jason Floyd, Craig Weinschenk,

Kristopher Overholt, and Glenn Forney in the Building and Fire Research Laboratory at the National

Institute of Standards and Technology and the VTT Technical Research Centre of Finland. They are theprimary authors of the Fire Dynamics Simulator and Smokeview, without which PyroSim would not exist.

They have been gracious in their responses to our many questions.

We would like to gratefully acknowledge the RJA Group for their collaboration with Thunderhead

engineering in the development of PyroSim. Feedback and testing from the engineers at RJA has

improved the usability and quality of PyroSim.

Development of PyroSim was originally supported by the National Science Foundation under Grants

DMI-0232401 and DMI-0349759. Any opinions, findings, and conclusions or recommendations

expressed in this material are those of the authors and do not necessarily reflect the views of the

National Science Foundation.


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Chapter 1.Getting Started

IntroductionPyroSim is a graphical user interface for the Fire Dynamics Simulator (FDS). FDS models can predict

smoke, temperature, carbon monoxide, and other substances during fires. The results of these

simulations are used to ensure the safety of buildings before construction, evaluate safety options of

existing buildings, reconstruct fires for post-accident investigation, and assist in firefighter training.

FDS is a powerful fire simulator which was developed at the National Institute of Standards and

Technology (NIST). FDS simulates fire scenarios using computational fluid dynamics (CFD) optimized for

low-speed, thermally-driven flow. This approach is very flexible and can be applied to fires ranging from

stove-tops to oil storage tanks. It can also model situations that do not include a fire, such as ventilation

in buildings. FDS and the Smokeview visualization program are both closely integrated into PyroSim.

The PyroSim interface provides immediate input feedback and ensures the correct format for the FDSinput file. Some highlights include:

Import CAD files to create and manage complex models.

High-level 2D and 3D geometry drawing tools.

Integrated parallel processing.

Flexible unit system that supports working in either metric or English units.

Tools to manage multiple meshes.

Multiple language translations.

HVAC (Heating, Ventilation, and Air Conditioning) systems integrated into the CFD simulation.

Import of existing FDS models. Integrated post-processing.

In summary, PyroSim helps you quickly and reliably build complex fire models.

Download and InstallThe current version of PyroSim is available on the web athttp://www.pyrosim.com.The Supportpage

allows you to sign up for a free trial version, purchase the software, and download the installer. This

page also provides instructions for installation, activation, moving to a different computer, and floating

licenses. There is no functional difference between the trial version of PyroSim and the full version.

When installing PyroSim, the installer will either upgrade an existing version or install PyroSim to a new

location. This behavior is based on the version. In the case of minor updates (e.g. upgrading from

PyroSim 2015.1 to PyroSim 2015.2), the installer will remove the older version and replace it with the

new version. When installing a major update (e.g. PyroSim 2013 to PyroSim 2015), the older version will

not be modified and the newer version will be installed to a different folder.
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Administrator privileges are required to install PyroSim. This is necessary because the installer adds

processes to the operating system for license management and parallel FDS simulation.

Some Modeling SuggestionsIn this section we make some suggestions that can help speed your model development. The big issues

most users will face are: selecting a mesh, defining your geometry, selecting a reaction, and defining thecorrect boundary conditions. We will broadly discuss each of those topics, but before you start thinking

about them please:

Take the time to work through the examples. On the PyroSim Tutorials page

(http://www.thunderheadeng.com/pyrosim/tutorials/)we provide a series of examples that

guide you through increasingly complex fire modeling concepts. It is worth your time to work

through these examples.

Remember to start small. When developing a new model, dont just rush in and make the final

model. Use small models to make sure you understand the details. For example, test your

sprinklers on a small model first. If you are using controls, practice on a simple case.

1. Selecting a mesh

The analyst will always need to balance solution time and accuracy. Reducing the mesh size by a factor

of 2, will result in approximately a factor of 16 more computation time (a factor of 8 due to the number

of cells and an additional factor of 2 due to reduced step size).

Two criteria will control the applicable mesh size:

Resolving the flow field.

Resolving the geometry.

For fire plumes, an initial mesh size estimate can be obtained as a fraction of the characteristic fire

diameter (), see Chapter 6 of the Fire Dynamics Simulator Technical Reference Guide Volume 3:

Validation. You can download a calculator from the PyroSim Resources web page. Initial calculations

should be done with a coarse mesh (maybe 5 ), but a mesh size study must be employed to analyze

the suitability of the mesh (maybe 20 ).

An example of a convergence study for jet fans (no fire) can be found in the series of posts Modeling Jet

Fansfound on the PyroSim Tutorials web page. Here the solution was compared with experimental data.

In some problems the mesh resolution must be selected to adequately represent the geometry. An

example where geometry controlled the mesh size is the modeling of a wood crib where each stick hada small diameter (see Modeling Fire, Part 4Combustion with HRR, Ignition, and Burn Away on the

PyroSim Support page).

2. Reactions

By default, no reaction is specified, a reaction is only needed if there will be a fire in the simulation. In

FDS, a reaction defines not only the fuel and the products but also the Heat of Combustion. Once the
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heat of combustion and the desired HRR is known, FDS calculates the fuel mass flow rate from the

surface.

For most situations, it is sufficient to use the Simple Chemistry model, where a single fuel species is

composed of C, H, O, and N that reacts with oxygen (air) to form the product species consisting of H2O,

CO2, Soot, N2, and CO. The user specifies the chemical formula of the fuel along with the yields of COand Soot, and the volume fraction of hydrogen in the soot, XH. A limited number of reactions are

included in FDS and can be added from the library.

See Chapter 12 of the FDS User Guide for a more detailed discussion of combustion. The PyroSim web

site provides Combustion and Fuel Composition calculators

(http://www.thunderheadeng.com/pyrosim/resources/).

3. Parallel Processing

Parallel processing can speed the solution. In general, our experience indicates that running on multiple

cores on the same computer offers the most significant improvement. Using multiple computers in a

cluster can make it possible to solve larger problems, but the communication delays between computers

tend to cancel the speed improvement of parallel processing.

The good news is that that standard installation of PyroSim includes support for parallel processing on

the same computer. All the user must do is define multiple meshes and then select Run FDS Parallel.

PyroSim includes tools to manage multiple meshes. One effective strategy is to first define a single mesh

that spans the entire model. Then use the PyroSim mesh splitting tool to create multiple meshes. You

can then change the resolution of selected meshes using the Refine Mesh option and all the meshes will

automatically stay correctly aligned.

4. FDS Snaps to the Mesh

All geometry in FDS is defined at the mesh resolution. Even if you input the geometry of an obstruction

or vent to lie between cell corner points, when FDS runs the solution, all the geometry will be snapped

to the grid.

If you are drawing your own geometry in PyroSim, you can select the Snap to Model Gridsoption that

will ensure that your geometry matches the grid. If you are using imported CAD geometry, you can

select the Thickenoption during import that will prevent the imported geometry from being defined as

a 2D face.

5. Numerical Instabilities are Usually Model ProblemsIn our experience, numerical instabilities that may occur during the solution are the result of an error in

the model, not an error in FDS. The numerical instability typically arises due to either a pressure increase

(or decrease) in a mesh. If you see this error, add a pressure sensor to your model and see what is

happening to the pressures. Problems typically occur because of how boundary conditions have been

defined.

Some common problems with boundary conditions include:
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Lack of an open vent on the boundary. One typical case is that a fire heats the air in a room but

there is no open vent, so the heated air expands and increases the pressure in the room which

eventually causes an instability. The solution is to make sure all rooms have open vents.

Imbalance on the flow conditions. This often occurs if the user specifies velocity boundary

conditions on both supply and exhaust vents in a room. If there is a fire in the room, the density

of the hot exhaust air is less than that of the ambient supply air, so velocity conditions result in

accumulation of mass in the room with a corresponding increase in the pressure. The solution is

to specify the velocity flow on the supply, but define the exhaust as an open vent (or vice versa).

The open vent will accommodate changes in density.

Flow boundary conditions into a closed space. This is more likely to occur when CAD data is

used to import geometry. If a supply is defined on a mesh boundary, it can intersect both the

model (as intended), but there can also be cells outside the model that are included in the

supply. The solution is to make sure there are open vents on the boundaries outside a model.

Using a Different FDS ExecutableEach PyroSim release comes bundled with FDS. A particular PyroSim release is designed and tested

against the bundled version of FDS. You can use PyroSim to run any version of FDS, however PyroSim

will generate the input file based on the bundled version of FDS and it is important to understand

differences in input format between the FDS versions before changing PyroSim's FDS version.

To change the version of FDS used by PyroSim:

1. Download and install a new version of FDS from NIST.

2. On the File menu, click Preferences.

3. Click on the appropriate Foldericon in the FDS Executionsection to select the executable you

want PyroSim to use.4. Click OKto close the Preferencesdialog.

Additional FDS and Smokeview DocumentationIn preparing this manual, we have liberally used descriptions from the FDS User's Guide (McGrattan, et

al., 2015). Links to the FDS Users Guide, the FDS Technical Reference, and the Smokeview Users Guide

are included in PyroSim on the Helpmenu. You can also download documentation, executables, and

verification and validation examples at:http://firemodels.github.io/fds-smv/.

Contact UsThunderhead Engineering

403 Poyntz Avenue, Suite B

Manhattan, KS 66502-6081

USA

Sales Information:[email protected]

Product Support:[email protected]

Phone: +1.785.770.8511
http://firemodels.github.io/fds-smv/http://firemodels.github.io/fds-smv/http://firemodels.github.io/fds-smv/mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]://firemodels.github.io/fds-smv/


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Chapter 2.PyroSim Basics

PyroSim InterfacePyroSim provides four editors for your fire model: the 3D View, 2D View, Navigation View, and the

Record View. These all represent your current model. If an object is added, removed, or selected in one

view, the other views will simultaneously reflect the change. Each view is briefly described below.

Navigation View: This view lists many of the important records in the model. It allows you to

organize your model geometry into groups such as room or sofa. Locating and modifying records

is often faster and easier in this view.

3D View: This view shows a 3D representation of your current fire model. You can explore the

model using different view controls. You can also control the appearance of the model with

options like smooth shading, textures, and object outlines. Geometric features can also be

changed.

2D View: This view is useful for quickly sketching geometry such as walls and furniture. You can

choose from three viewing planes and perform many useful geometric manipulations.

Record View: This view gives a preview of the FDS input file that will be generated for the

simulation. It also provides a way to add custom records that will not be processed by PyroSim,

but will be sent to FDS.

Navigation ViewThe navigation view is a tree-like view on the left side of the PyroSim main window. An example of this

view in use is shown inFigure 2.1.When you right-click on an item in this view, a list of the functions

PyroSim can perform on that item is shown. To rearrange objects in the Navigation view, make a

selection and then drag the object(s) to the new location.


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Figure 2.1. Using the context menu in the Navigation View

3D ViewUse the 3D view to rapidly obtain a visual image of the model and perform some drafting. In this view,

the user can navigate through the model in 3D and select objects. This view also provides display filters

to quickly show/hide entire categories of objects or switch between floors. In addition, any drafting that

requires objects to be snapped to faces of other objects, such as drawing a vent on an obstruction or

attaching a measuring device to a solid can be easily achieved in this view. For more information on

drafting, seeChapter 9.

Navigation/Selection

There are several tools that can be used to navigate the model and select objects. The tools for the 3D

view are found in the navigation toolbar above the 3D view as shown inFigure 2.2.

Figure 2.2. 3D navigation toolbar

Select/Manipulate Tool ( ): This general-purpose tool can be used to perform most navigation

activities.

o Selection: Left-click an object to select it. Drag the left mouse button to draw aselection box and select all objects within the box. Double-click the left mouse button to

select and open a properties dialog for the object under the cursor. Hold ALTwhile

performing selection to select the hierarchical parent of the object under the cursor.

Right-click to show a context menu for selected items under the cursor.

o Panning: Drag the middle mouse button to panthe model.

o Orbiting: Drag the right mouse button to orbitthe model.


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o Manipulating: If a single object is selected, it may show manipulation handles (blue dots

or faces). Left-click one of the handles to begin manipulation or drag the left mouse

button to perform manipulation in one gesture. For more information on manipulation,

seeEditing Objects on page 81.

Orbit Tool ( ): This is another general-purpose tool that may be more familiar to existing

PyroSim users, but it is more limited than the Select/Manipulate Tool.

o Selection: This is the same as with the Select/Manipulate Toolexcept that a selection

box cannot be drawn.

o Orbiting: Drag any mouse button to orbit.

o Panning: Hold the SHIFTkey down while dragging any mouse button to pan.

o Zooming: Hold the ALTkey down while dragging any mouse button to zoom.

o Manipulating:This tool cannot perform manipulation.

Roam Tool ( ):This tool allows the user to move into the model rather than viewing it only

from the outside as shown inFigure 2.4.This tool can take some experimentation, but once

mastered, it can provide unique views of the model.

o Selection: This is the same as with the Orbit Tool.

o Looking:Drag any mouse button to look around. This pivots the camera about the

cameras location, similar to a first-person video game.

o Moving:Hold the ALT key while dragging a mouse button to move the camera up and

down along the Z axis. Hold the CTRLkey while dragging a mouse button to move the

camera forward, backward, and side-to-side in the cameras XY plane.

Pan Tool ( ), Zoom Tool ( ), Zoom Box Tool ( ):These tools break out the functionality of

the above tools so that dragging any mouse button will perform the needed action.

Figure 2.3. Exterior view of model (PyroSim model by John McKinney)


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Figure 2.4. Interior view of model looking at roof and bleachers

Zooming

The model can also be zoomed in and out with any of the navigation tools by using the scroll wheel.

Scrolling up zooms in and scrolling down zooms out. With all but the Roam Tool, using the scroll wheel

will zoom in on the point under the cursor. With the Roam Tool, the scroll wheel only zooms the center

of the view.

Resetting the View

At any time, the cameras view can be resetto see the entire extents of the model by clicking the Reset

Viewbutton ( ) or pressing CTRL+r. In addition, the camera can be reset to only the currently selected

objects by clicking the Reset to Visiblebutton ( ) or pressing CTRL+e. Resetting the view also has the

effect of changing the orbit center when orbiting.

Orbiting

Orbitingis the action of spinning the camera about its focal point, which is the center of the model or

center of the selection, depending on which resetaction was last performed. By default, orbit works as

if there is an invisible sphere around the model on which you click and drag the mouse to spin.

Alternatively, orbiting can be performed similarly to Smokeview by going to the Viewmenu and

selecting, Use Smokeview-like Navigation. In this mode the camera spins about the Z axis with left and

right mouse movements and about the local X axis with up and down movements.

Filtering

There are several ways to filter the objects shown in the 3Dview. Filtering can be performed with

clipping planes that are associated with floors or through filter buttons that can quickly show/hide

categories of objects.


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To use clipping, the user must first define floors for the model as discussed inFloors on page 56.Once

the floors are defined, a floor can be selected by using the Floor Drop-downabove the 3Dor 2Dview as

shown inFigure 2.5.

Figure 2.5. Floors drop-down

Once a floor has been selected, its clipping planes will be applied to the entire scene to only show

objects within the clipping region.

Filtering can also be performed using the filter toolbar buttons as shown inFigure 2.6.

Selecting/deselecting these buttons will quickly show/hide all objects of a specific type, such as

obstructions, holes, vents, etc.

Figure 2.6. Filter toolbar

Filtering can also be applied to meshes but in a slightly different way. Instead of showing/hiding all

meshes, the user can selectively show/hide three different elements of them using the mesh filtertoolbar shown inFigure 2.7.This toolbar selectively allows viewing mesh grid lines, mesh boundaries,

and mesh outlines.Figure 2.8 shows the different mesh elements. In the figure, A shows the grid lines, B

shows the boundary, and C shows the outline.

Figure 2.7. Mesh filter toolbar


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A B C

Figure 2.8. Filtering mesh elements

Background images attached to floors can be quickly shown/hidden using the Show Background Image

filter button next to the floor drop-down.

2D ViewThe 2Dview is mostly the same as the 3Dview with some key differences:

The 2D view provides pre-set, orthographic views of the model. The view can be set to thetop

, front , or side views.

The 2D view does not have the Orbitand Roam tools.

The Select/Manipulate tool pansthe model when dragging the right mouse button rather than

orbiting.

Drafting is performed differently in the 2D View. For more information, see2D versus 3D

Drawingon page 66. Snapping can be performed to either the solution mesh or to a user-defined sketch grid.

When snapping to a solution mesh, the mesh grid lines are always shown, the boundary is never

shown, and only the outline of the mesh can be optionally shown.

Floor clipping is slightly different. For more information seeFloorson page 56.

Record ViewThe Record Viewis shows an up-to-date display of the FDS input file currently represented by the

PyroSim model. This view is divided into two sections, the Model Recordsand the Additional Records.

Model Records

This read only sections allows the user to see an exact copy of the file that will be input into the FDS

simulator based on their current model. The user adjust font size of this using the Increase Font Size

and Decrease Font Size buttons at the top of the page. Other settings related to the file display can be

toggled through the Preferences.menu item.


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Additional Records

Due to the complexity of the FDS simulator, it is difficult to support all possible records and input files.

The Additional Recordssection of the Record Viewcan be used to inject lines of text straight into the

FDS input file.

Snapshots of DisplayImages of the current display can be saved to a file by opening the File menu and clicking Snapshot.The

user can specify the file name, image type (png, jpg, tif, bmp), and the resolution. A good choice for

image type is Portable Network Graphics (png).

PreferencesPyroSim preferences can be set by going to the Filemenu and choosing Preferences.Any changes to the

preferences will be set for the current PyroSim session and be remembered the next time PyroSim is

started. The preferences are split into several groups, includingPyroSim, Record View, FDS, SMV, and

Displaypreferences.

PyroSim Preferences

These describe global PyroSim preferences as shown in Error! Reference source not found..

Figure 2.9 PyroSim preferences

Format FDS file for easy reading - controls the format of real numbers in the FDS input file created by

PyroSim. When this is checked, a real number is written such that if the absolute value is >= .001 and Smokeview Viewpoints. The latter is useful if

a simulation has already been run and the views are subsequently changed in PyroSim. Explicitly re-

writing the INI file allows the viewpoints to be updated for viewing in Smokeview without having to re-

write the FDS file or running the simulation.

There are some limitations to how PyroSim views are exported to the INI file:

Only views with viewpoints that were saved from the 3D Vieware written.

Camera roll information is not exported, which means that the Smokeview viewpoints might

not match the orientation in PyroSim perfectly. The only way to guarantee that the orientation

matches is to use the Roamtool in PyroSim to orient the camera.

Zoom information is not exported.

Only section boxes that have not been rotated are exported.

Sometimes the geometry is not visible in Smokeview from an exported viewpoint due toincorrectly chosen near and far clipping planes in Smokeview.

In addition, if a view was saved in PyroSim with the Roamtool active, the Rotation typein Smokeview is

set to Eye centered. For all other navigation tools, the Rotation typein Smokeview is set to 2 axis.

Smokeview viewpoints may also be imported into PyroSim. This is useful if additional views have been

specified in Smokeview while viewing the results and those viewpoints should be preserved in PyroSim.

To import Smokeview viewpoints, perform the following:

1. On the Filemenu, select Import FDS/CAD File.

2. Choose the INI file that accompanies the SMV file that was viewed.1

After importing, a new view group is added, containing one PyroSim view for each Smokeview viewpoint

that was in the INI file.

1Importing a Smokeview INI file also requires that the corresponding SMV file be read by PyroSim. If an SMV file

with the same name as the INI file is not found in the same file directory as the INI file, the user is asked to choose

the SMV file.


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Chapter 4.Working with FilesSeveral files are used when performing a fire analysis using PyroSim. These include the PyroSim model

file, the FDS input file, and FDS output files. This section describes how to load and save files in the

formats supported by PyroSim.

Creating a New PyroSim ModelWhen PyroSim is started, it begins with an empty model. You can close the current model and create a

new empty model by opening the Filemenu and clicking New. PyroSim always has one (and only one)

active model.

Saving a PyroSim ModelThe PyroSim model file (PSM) is stored in a binary format that represents a PyroSim model. The PyroSim

model contains all the information needed to write an FDS input file, as well as additional information

such as obstruction grouping, floor heights, background images, and textures. This format is ideal for

sharing your models with other PyroSim users.

To save a new model:

1. On the Filemenu, click Save.

2. Enter the file name and click the Savebutton.

Open a Saved PyroSim ModelPyroSim model files have a PSM extension. To open a saved model:

1. On the Filemenu, click Open.

2. Select the file and click the Openbutton.

A list of recently opened files is also available. To open recent files, on the Filemenu, click Recent

PyroSim Files, then click the desired file.

PyroSim has an auto-save feature which stores a copy of your current model every 10 minutes. This file

is automatically deleted if PyroSim exits normally, but if PyroSim crashes, you can recover your work by

opening the autosave file. It can be found either in the same directory as your most recent PSM file, or

in the PyroSim installation directory if your model was unsaved.

For more information about opening files saved with previous versions of PyroSim, please refer to

Chapter 23.Appendix A.

Preventing Changes to a ModelPyroSim supports write protection for a model. When write protection is enabled, users cannot modify a

model (e.g. change geometry, edit surface properties, etc). This option can be enabled with or without

password protection. If a model is write-protected, PyroSim will display notification in the application

title bar.


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To add write protection to a model:

1. On the Filemenu, click Write Protection...

2. Click OK.

The model will now be write-protected. Since a password was not used, a password will not be required

to remove write protection.

To remove write protection from a model:

1. On the Filemenu, click Write Protection...

2. Click OK.

The model can now be edited. If needed, the dialog will require a password to release the lock.

Importing FDS ModelsPyroSim allows you to import existing FDS input files. When you import an FDS file, PyroSim will create a

new PyroSim model from the imported file. During import, PyroSim will check for the validity of each

record. If errors are detected, you will be notified. You may then make the required corrections and

attempt to import the file again.

To import existing FDS models into PyroSim:

1. On the Filemenu, select Import FDS/CAD Fileor click the Importbutton on the main

toolbar.

2. Select the FDS file and click Open.

PyroSim supports file import for versions 4, 5, and 6 of FDS. For more information about opening files

compatible with version 4 or 5 of FDS, please refer toAppendix A.

Exporting FDS ModelsPyroSim also allows you to explicitly export the current model to an FDS input file. You can manually edit

the file to take advantage of advanced FDS features, or to easily transfer the input file to a different

machine or special version of FDS.

To export an FDS file:

1. On the Filemenu, click Export, then click FDS File... or click the Exportbutton on the main

toolbar.2. Enter the file name and click Save.

The file exported by PyroSim will be compatible with version 6 of FDS.


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Importing CAD filesPyroSim can import geometry from several CAD formats, including AutoCADs DXF (Drawing Exchange

Format), DWG, FBX, DAE, OBJ, and STL files. Each type of file provides a variety of geometry that can

either be directly represented as obstructions or as drawing guides in the PyroSim model.

DXFa basic CAD format provided by Autodesk. This format supports robust geometry types,including 3d faces, lines, and text, but it does not support appearance information, such as

textures, lighting parameters, etc.

DWGsimilar to DXF, but it also has basic support for appearances, including textures. It has

only basic support for mapping textures onto objects, however, and few CAD applications can

export DWG files. Some, such as Revit, exclude material and texture information (see more

information inImporting Revit Files on page 28).

FBXprovides support for 3d faces only, but it has very good support for appearance

information and texture mapping. In addition, many 3D modeling applications have built-in

support for exporting FBX files. Unfortunately, this format has no information about whether

objects are solid, so PyroSim treats them as collections of thin faces. This can cause issues if

holes are intersected with objects from these files, as smoke will be able to enter the cavity of

solid objects. With the exception of holes, though, this is still a good format for importing 3D

building models into PyroSim.

STLa basic file format that is simply a listing of triangles. There is no appearance or texture

information.

Unlike FDS import, which completely replaces the current PyroSim model, CAD import appends the data

to the current model. This facilitates the ability to import data from several CAD files into one PyroSim

model. This is useful when there is one blueprint per floor of a building or a 3D building has been split

into several sections, each in a separate file.

To import one of these files, under the Filemenu, select Import FDS/Cad Fileand select the desired

file. STL files will import as shown inImporting STL Files on page 27.For non-STL files, a step-by-step

dialog will open as shown inFigure 4.1. NOTE: CAD files store display information in objects called

Materials. These materials are converted intoappearance objects and surfaces in PyroSim. They do

not correspond with the FDS definition of a material.


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Figure 4.1: CAD import dialog

1. FBX Exporter: If an FBX file is being imported, this prompt will ask what software was used to

export the file. If a SimLabFBXplugin was used to create the FBX file, choose SimLabfrom the

drop-down box; otherwise; choose Unknown. This selection controls the default settings in the

subsequent prompts. In some cases, PyroSim is able to detect whether the file was exported

using a SimLab plugin and will select this option automatically.

2. Units: The next prompt asks the user to select the base unit in which the CAD file was created.

If the drawing was saved in a more recent file format, the prompt will default to the unit type

stored in the file. The dialog box shows the models width, depth, and height based on the

selected unit as a guide for selecting the unit.

3. Import Settings: The next prompt allows the user to control how some of the data is imported

and to correct some data that may have been written incorrectly by the files CAD exporter.

Normal Tolerance (DWG/DXF only)controls the quality of curved objects. Decreasing

this value produces higher quality objects at the expense of slower rendering speed. The

default value of 15provides a nice balance.

NURB Gridlines (DWG/DXF only)controls the quality of NURB surfaces. Increasing this

value gives higher quality curves at the expense of slower rendering speed. The default

value of 5provides a good balance.

Auto-correct inverted polygonssome CAD files contain information about the normal

of a polygon that affects how the polygon is lit. In some cases, the normal may not

match the orientation of the polygon, which can cause the polygon to appear too dark.

Selecting this option will allow PyroSim to try to detect these cases and correct theorientation of the polygon so it may be lit correctly. This option works well in most

models and is generally safe to leave on.

Merge identical materialssome CAD exporters (namely SimLabs Revit FBX plugin) will

create a unique material (appearance) per object in the file, which may lead to hundreds

or thousands of materials that have duplicate properties. Selecting this option allows


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the materials with duplicate properties to be merged into one material, significantly

reducing the number of materials in the model with no loss of quality.

Ignore transparency color (FBX only)in FBX files, material transparency is determined

from a transparency color and factor. Some CAD exporters (SimLabs FBX plugins)

export the color incorrectly. Selecting this option will allow PyroSim to ignore the

transparency color in the FBX file and only use the transparency factor, which allows

transparency in these files to import correctly. This option should only be selected if it is

known that the file came from a SimLab plugin or there are transparency problems

without it selected (For example, objects that should be transparent are not or vice

versa).

4. Options: This prompt allows the user to specify more options for import. Before this prompt is

shown, PyroSim will attempt to discern if the CAD file contains a 2D Floorplan or a 3D Model and

will select default values for the options based on the detected type.

Linescheck to import lines in the file (default=checked only for floorplans)

Facescheck to import faces in the file (default=checked only for 3D models)

Move geometry to Zif checked, all imported geometry will be offset so that the

minimum Z lies in the specified Z plane (default=checked only for 2d floorplans).

Flatten so geometry lies in one planeif checked, all geometry will be scaled in the Z

dimension by a very small scale (1e-9). This is useful for floorplans that have entities

drawn in several planes. This option will flatten them all into one plane.

(default=checked only for 2d floorplans).

Add a blank rectangle to obscure lower floorsif checked, a solid rectangle of the

specified color will be added to the model. This is useful to obscure geometry located on

lower floors. The imported rectangle will not become an obstruction and will be

excluded from the simulation. (default=checked only for 2d floorplans).

Choose Finishto import the file.

When PyroSim imports a CAD file, it will treat all 3D face data as obstructions and all other data (lines,

curves, etc.) as separate CAD data. If an object in the file contains both face and CAD data, the entity will

be split into two entities so that CAD data can be easily deleted or hidden after import using the CAD

filter button on the 3D/2D View toolbar (seeFiltering on page 8).

An object with CAD data can be snapped to while drawing in PyroSim but is not converted to any type of

FDS geometry.

In DWG and DXF files, an entity with face data will either be treated as a single, solid obstruction with

some volume or as a collection of thin obstructions depending on the entity type in the DWG/DXF file.

These objects will be represented as FDS geometry. The following DWG/DXF entity types are treated as

solids in PyroSim:

3D Solid

Mass Element


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Mass Group

Roof

Slab4

Roof Slab

Stair

Wall4

Door

Window

Curtain Wall

Curtain Wall Unit

Curtain Wall Assembly

Structural Member

All other entities and objects from other CAD formats that contain faces are treated as collections of

thin obstructions by PyroSim. They cannot be reliably treated as solid since there is no guarantee that

their faces form a closed and non-self-intersecting shell or that this would even be desired.

Once the file is imported, PyroSim creates a hierarchy of groups and objects, such that there is one top

group, named after the file. The next levels depend on the imported file type. For non-DWG/DXF files,

the structure will mimic the node structure in the source file. For DWG/FXF files, the next level contains

a group for every layer containing geometry. Under each layer group there are one or more objects

representing the entities in the file. The following illustrates the hierarchy as it would appear in the

Navigation View:

FileName

o Layer1 Entity1

Entity2

o Layer2

Entity3

Entity4

o

If the DWG/DXF file contains a block insert and the block contains entities from multiple layers, the

block insert is split into several PyroSim objects, one for each layer of the blocks originating entities. If

all the entities in the block are from the same layer, however, there will be one resulting PyroSim object

4While PyroSim allows the user to draw walls and slabs, it will not convert DWG/DXF wall and slab entities to

native walls and slabs, due to the complexity with which walls and slabs can be represented in the DWG/DXF file.

They will instead be represented as collections of individual faces, representing one solid object.


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that will belong to the group corresponding to the blocks entities layer rather than the block inserts

layer.

Importing STL Files

PyroSim can also import objects from STL files, which are simply listings of triangles. Usually, each STL

file represents the shell of one 3D solid object. To import an STL file, perform the following:

1. On the Filemenu, select Import FDS/CAD Fileor click the Importbutton on the main

toolbar.

2. Select the desired STL file and click Open.

3. Enter the import options in the STL Import Options dialog as shown inFigure 4.2.

4. Click OK to begin import.

Figure 4.2. STL Import Options dialog

In the STL Import Optionsdialog, the following options can be specified:

File Unitsthe units used to store the 3D coordinates in the STL file.

Vertex weld tolerancea distance used to determine how far apart vertices must be to be

considered separate.

Resulting Geometry Typechoose Obstructionto treat the resulting objects as obstructions

and Holeto treat them as holes.

Surfacethe surface to apply to the resulting obstructions if applicable.

Convert to solid obstructionswhether to treat the resulting objects as solid obstructions. Ifthis is unchecked, each resulting object will be a collection of thin obstructions.

Because the STL file is simply a listing of triangles, there may be more than one object represented in

the file. PyroSim will use the vertex weld tolerance to detect triangle connectivity and determine if there

are several, disconnected sets of faces in the file. If there are, there will be one resulting PyroSim object

per connected set of faces.


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In addition, if the solid option is enabled or the objects are being treated as holes, import will only

succeed if each face set is detected as a closed shell by PyroSim.

Importing Revit Files

While PyroSim cannot directly import Autodesk Revit files (RVT), there are several ways to export the

data from Revit into a file format that PyroSim can read. Each method has advantages anddisadvantages as discussed below.

Revit to DWG (direct):The first method is to export a DWG directly from Revit, which can then

be imported into PyroSim. While simple to perform and only requires Revit, this method loses

all information about materials, including textures, due to Revits limited DWG support. To

perform the export in Revit Architecture 2014, perform the following:

1. Open the desired RVT file within Revit Architecture.

2. Click the Revit icon at the top left .

3. Select Export->CAD Formats->DWG.

4.

In the DWG Exportdialog, for Export, select

.

5. For Show in list, select Views in the Model.

6. Click the Check Nonebutton, and then in the view table, select the check box for3D

View: {3D}(Other views may be chosen, but the DWG will only contain entities

visible in the selected views).

7. Click the Nextbutton and choose a file name for the DWG file.

8. Click OKto create the DWG.

9. Import the DWG into PyroSim.

Revit to FBX (direct):This method exports an FBX file directly from Revit, which can then be

imported into Pyro

Documents

PyroSim UG